1. Field
One or more embodiments of the present invention relate to a write strategy method, medium, and apparatus, and more particularly, to a method, medium, and apparatus, including an optical recording/reproducing method, medium, and apparatus, automatically generating and providing an optimized write strategy in accordance with a specific writing characteristic of each optical disc drive.
2. Description of the Related Art
In order to write predetermined data to an optical medium, a laser diode is modulated in accordance with an encoded electric signal. In this case, a pulse type of the laser diode is modulated so that an optical recording/reproducing apparatus has an optimized writing characteristic. Determining the pulse type of the laser diode corresponds to designing a write strategy. However, in order to design the write strategy, an innumerably large number of write strategy parameters, which specifically represent the pulse type, are separately defined.
Here, the recording/reproducing apparatus is a recording device, such as an optical disc drive, that may write data by using a light source such as a laser. Examples of the corresponding medium include a compact disc-recordable (CD-R), a digital video disc (DVD), a digital video disc-recordable (DVD-R), and a compact disc-rewritable (CD-RW).
Various types of data may be written to or stored on the underlying optical recording medium. The types of data generated by using a non return to zero, inverted (NRZI) modulation, method will now be described with reference to FIGS. 1A through 1D. Hereinafter, a signal generated by using the NRZI modulation method will be referred to as an NRZI signal.
FIG. 1A illustrates write strategy parameters and a type of laser diode pulse which are used for a CD-R, a DVD-R, or an organic blue-ray disc-recordable (BD-R).
Referring to FIG. 1A, a referenced data signal 101 corresponds to an actual data signal to be written. The waveform of the data signal 101 is generated by using an NRZI modulation method. The data signal 101 is shown as having a value of 1000001. Here, a logic high level is referred to as a mark and a logic low level is referred to as a space.
A laser diode signal 103 corresponds to a laser diode signal in accordance with a write strategy applied to a DVD-R or an organic BD-R. That is, in order to write the data signal 101, the write strategy has to be designed so as to generate the laser diode signal 103 as illustrated in FIG. 1. Referenced parameters PB, PC, dTtop, OD, dTLP, dTE, TLP and the like are referred to as the write strategy parameters. That is, in order to design the write strategy, each of the write strategy parameters has to be defined.
FIG. 1B is a diagram illustrating write strategy parameters and a type of laser diode pulse which are used for a CD-RW high speed (HS)/low speed (LS), a DVD-R normal speed (NS), a BD-R, or a blue-ray disc-rewritable (BD-RW) LS.
Referring to FIG. 1B, in order to write a data signal 111 on a CD-RW HS/LS, a DVD-R NS, a BD-R, or a BD-RW LS, a laser diode signal 113 has to be generated. Here, the write strategy parameters such as PE, dTtop, POD, and TMP have to be defined.
FIG. 1C is a diagram illustrating write strategy parameters and a type of laser diode pulse which are used for a CD-RW ultra speed (US) or a digital video disc-rewritable (DVD-RW) HS.
Referring to FIG. 1C, in order to write a data signal 121 to a CD-RW US or a DVD-RW HS, a laser diode signal 123 has to be generated. All parameters illustrated in FIG. 1C have to be defined in order to design a write strategy of the CD-RW US or the DVD-RW HS.
FIG. 1D is a diagram illustrating write strategy parameters and a type of laser diode pulse which are used for a BD-RW HS.
Referring to FIG. 1D, in order to write a data signal 131 to a BD-RW HS, a laser diode signal 133 has to be generated. All parameters illustrated in FIG. 1D have to be defined in order to design a write strategy of the BD-RW HS.
The write strategy parameters, such as dTtop, TOD, Ttop, dTMP, TMP, dTLP, TLP, and dTE which are illustrated in FIGS. 1A through 1D, are separately and differently defined in accordance with the standards and type of the recording medium, such as a writing speed, a writing characteristic of a manufacturer, set deviations of an optical disc drive, and a writing environment. However, in general, the manufacturer of the optical disk drive optimizes and determines the write strategy parameters during manufacture in accordance with the standards and type of the recording medium, such that select write strategy parameters are fixed post-manufacture. In this case, the manufacturer determines the optimized write strategy parameters by analyzing periodical lengths of an NRZI pattern and the amount of timing jitter. The determining of the optimized write strategy parameters is referred to as the designing of a write strategy.
FIG. 2 illustrates a conventional method of designing, storing, and authenticating a write strategy for an optical recording medium.
Referring to FIG. 2, the conventional method includes operations 210, 220, and 230. First, in operation 210, a manufacturer designs the write strategy by analyzing periodical lengths of an NRZI pattern and the amount of timing jitter and by determining optimized write strategy parameters.
In operation 220, the write strategy designed in operation 210 is stored in firmware. The write strategy may be stored in a memory of an optical recording/reproducing apparatus by performing porting, compiling, and downloading processes.
The optical recording/reproducing apparatus may, thus, store the write strategy optimized for a recording medium, a writing speed, and information on a manufacturer of the recording medium. The stored write strategy will be read and executed later.
Then, a writing operation is performed by using the write strategy determined in operation 210. By performing the writing operation, the write strategy may be authenticated in terms of whether it has been correctly designed, in operation 230. After the authenticating, if the quality of the write strategy is below an acceptable quality level, the write strategy is modified or redesigned by tuning certain parameters.
However, several hundred types of optical disc drives are produced by different manufacturers. Accordingly, quite a large amount of time is required to design a write strategy by determining optimized write strategy parameters of each type of optical disc drive. Also, a large part of a production period of the optical disk drive involves designing the write strategy.
Furthermore, a certain optical recording/reproducing apparatus may not easily determine all optimized write strategies for all conventionally released optical recording media produced by all manufacturers.
In the above-described conventional method, an innumerably large number of combinations of write strategy parameters for each optical recording medium may not be easily measured and thus optimized write strategy parameters may not be easily determined.
Still further, in optical recording/reproducing apparatuses of the same model, write strategy parameters may have deviations for different settings. However, the conventional method does not consider these set deviations and thus does not compensate for the set deviations.
In addition, when a new optical recording medium is released, a newly designed write strategy applicable to the new optical recording medium and firmware for a corresponding optical recording/reproducing apparatus has to be upgraded. That is, a firmware upgrade has to be performed in order for a conventional optical recording/reproducing apparatus, which is using the new optical recording medium, to execute an appropriate optimized write strategy.
The write strategy is very important for determining the quality of all data to be stored in and be read from an optical recording medium. However, as described above, the conventional methods may not compensate for deviations of write strategy parameters that exist regarding the optical recording medium and the optical recording/reproducing apparatus. Furthermore, when a new optical recording medium is released, conventional methods may not appropriately cope with new optical recording media and may not generate and use an appropriate or optimized write strategy.